1899] PEAR AND CHERRY SAWFLY. 109 



" Judging, however, from the occurrence of the eggs, larvae in all 

 stages, pupae, and perfect insects at one and the same time, I am 

 inclined to think that, like the Grooseberry Sawfly {Neinatus ribesii) — in 

 favourable seasons at least — there is a succession of broods from May 

 till October. 



" The exact position of the cocoons in the earth is of importance 

 as giving us the amount of surface soil to remove, and also the 

 particular places to which we should direct special attention — viz. the 

 wall below the surface of the soil, and the bark of the larger roots at 

 the base of the tree {see ' Methods of Prevention,' below). 



" The application of hot lime as a top-dressing certainly appears to 

 have had no effect upon the pest. It was applied about twelve months 

 ago, and now forms a thin hard layer between the stones ; one would 

 think it sufficiently hard in places to prevent the larvae now getting 

 through it, or the iiiuKjines finding their way through it after escaping 

 from the cocoons ; but one fragment of the lime which I successfully 

 removed has a boring completely through it, as well as through a layer 

 of cloth (an old ' shred' with nail attached) which had fallen into the 

 lime while in a plastic state. 



" I can offer no comment upon the application of paraffin emulsion, 

 only that my friend fully assured me that it had not the slightest effect 

 upon the Slugworms. I fully believe, however, that, had the application 

 of Paris-green been applied to the whole of the tree, and the strength 

 doubled, it would have had the desired efiect. 



^' Methods of Prevention. — Remove surface soil three to four inches 

 deep all along the wall beneath the infested tree, to a little distance 

 beyond the longest branches, and to about eighteen inches distant from 

 the wall ; also expose all the larger roots at base of tree. Scrape and 

 carefully remove all adherent soil, &c., from the wall and the roots and 

 root-forks. A trowel or ' hard chisel ' is suitable for scraping the wall, 

 and a blunt piece of wood suitably shaped should be used for scraping 

 the bark of the largest roots. The scrapings should not be allowed to 

 fall to the ground, but collected as they fall, and all should be destroyed 

 by fire ; on no account should they be thrown to the rubbish-heap. To 

 ensure success, paint the ivall with pure paraffin, and the roots with a 

 soap-wash applied with a stift' brush. Give a top-dressing of suitable 

 soil to replace the surface soil removed. The above rule applies 

 similarly to the surface soil ; this also should be subjected to the 

 action of fire, or buried in a deep hole, in order that the pupfB may be 

 destroyed." — (R. N.) 



I have given the above notes in extenso, as Pear trees against walls 

 are so liable to be attacked by the so-called "Slugworm" that the 

 minute details of what may be happening in many instances is of 

 interest practically, and several of the points are well worth record. 



